Modern mobile communications increasingly tend to provide multimedia services that are transmitted with a high speed to users. FIG. 1 is a schematic diagram illustrating a system architecture of System Architecture Evolution (SAE).
In FIG. 1, User Equipment (UE) 101 is a terminal device configured to receive data. Evolution-Universal Terrestrial Radio Access Network (E-UTRAN) 102 is a radio access network, which includes a macro base station (eNodeB/NodeB, eNB) used for providing a radio network access port for the UE. Mobile Management Entity (MME) 103 is configured to manage mobile context, session context and security information of the UE. Service Gateway (SGW) 104 mainly provides functions of a user plane. MME 103 and SGW 104 may be in a same physical entity. Packet data network gateway (PGW) 105 provides functions like charging and lawful interception. PGW 105 and SGW 104 may be in the same physical entity. Policy and Charging Rules Function Entity (PCRF) 106 is configured to provide a Quality of Service (QoS) policy and charging guidelines. Service GPRS Supporting Node (SGSN) 108 is a network node device configured to provide routing for data transmission in a Universal Mobile Telecommunication System (UMTS). Home Subscriber Server (HSS) 109 is a home subsystem of the UE, and is configured to protect user information including a current position of the UE, an address of a service node, user security information, packet data context of the UE, etc.
3GPP version 12 (Rel-12) proposes a requirement of small cell enhancement. Target scenes of the small cell enhancement include a scene in which there is the coverage of a macro cell and a scene in which there is no coverage of the macro cell, indoor enhancement and outdoor enhancement, ideal backhaul enhancement and non-ideal backhaul enhancement, as shown in FIG. 2.
Under the situation where there is the coverage of the macro cell, carrier aggregation between different base stations may be employed. The macro cell and a small cell may work in different frequency bands. There are multiple architectures employing the carrier aggregation between different base stations, such as the architecture based on Radio Access Network (RAN) splitting and the architecture based on Core Network (CN) splitting. Base stations involved in the carrier aggregation may be divided into a master base station (may be called MeNB) and a secondary base station (may be called SeNB). Interaction between the SeNB and the core network on a control plane is performed through the MeNB. Main RRC functions and control of the UE at an air interface are also located in the MeNB. The architecture based on the RAN splitting means that a data bearer is set up on the MeNB and the SeNB, and the data is forwarded to the SeNB through the MeNB. The architecture based on the CN splitting means that for a bear set up on the SeNB, the data is directly send from the SGW in the core network to the SeNB, and the data at the user plane is not forwarded through the MeNB.
Supporting service local breakout under the small cell architecture may reduce backhaul load. Currently, there is no solution about how to set up the local breakout in the small cell.